IMAGE FORMING APPARATUS

An image forming apparatus comprising an image bearing member, a developer bearing member, a drive unit for driving the image bearing member and the developer bearing member in varied peripheral speeds, a control unit, a developing voltage application unit, a supply member for supplying a developer to the developer bearing member, and, a supply member voltage application unit, wherein the control unit executes a first image forming mode in which a rotational peripheral speed ratio between surface movement speeds of the developer bearing member and the image bearing member is not more than 1 and a second image forming mode in which the rotational peripheral speed ratio is larger than 1, and, the control unit controls the drive unit so that a difference between developing voltage and supply voltage becomes larger in the second image forming mode than in the first image forming mode.